A vehicle seat belt is provided with multiple seat belt tension sensors providing
output signals that are received and averaged. Signals having values outside a
band around the average are dynamically tested against a signal from an occupant
weight sensor, vertical seat accelerometer or other sensor indicating expected
vertical acceleration of an occupant restrained by the seat belt. This test provides
variance values and time-averaged values of each signal, derives a reference value
for each signal and compares the variance value for each signal to its reference
value. If the comparisons indicate that the dynamic variance of the signals is
significantly different, the signal is declared invalid and the average value is
recalculated without the invalid signal. The final average signal after removal
of all invalid signals determines the belt tension value, which may be used to
compensate a weight sensor signal in an occupant characterization system to help
control deployment of a vehicle airbag.
